Settlement terminal

ABSTRACT

To prevent skimming of card data used in electronic payment, attention is given to a phenomenon occurring in performing the fraudulent act of attaching a skimmer to a settlement terminal—namely that the settlement terminal is turned on and off several times. Detected power-on/off abnormalities are determined in accordance with an abnormal power-on/off definition stored in a memory. This may, for example, be that when the number of times the settlement terminal is turned on or off within a specified time period exceeds a predetermined number, the power-on/off is defined as abnormal power-on/off. When the power-on/off is determined to be abnormal, warning information is sent to a settlement organ computer.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based on Japanese Priority DocumentP2004-019559 filed on Jan. 28, 2004, the content of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a settlement terminal having asettlement function, and particularly relates to a settlement terminalwhich is connected to a settlement organ computer in a settlement organthrough a communication line.

2. Discussion of the Background

Electronic payment by use of various cards, instead of cash, is widelyused these days. The various cards used for electronic payment include,for example, credit cards and cash cards used in debit card payments.

The electronic payment is executed with the use of a settlementterminal. The settlement terminal reads card data from the various cardsand inputs personal identification numbers in settlement processing. Ina settlement processing with a credit card, by way of example, thesettlement terminal reads, as card data, a credit card number in orderto execute the settlement processing. In a settlement processing with acash card, used in a debit card payment, the settlement terminal readsan account number of a bank as card data, and inputs a personalidentification number in order to execute the settlement processing. Ina settlement processing, the settlement terminal creates inquiryinformation on the basis of card data read from the various cards andthe inputted personal identification number. The inquiry information issent through a communication line to a settlement organ computer in asettlement organ to execute an authorization. Upon receiving an approvalfrom the settlement organ computer in response to the inquiry, thesettlement terminal executes the settlement processing.

In accordance with the widespread use of electronic payment, theft ofcard data stored on cards becomes a problem. Card data is fraudulentlyobtained by skimming, by which information recorded as card data isfraudulently read and copied. Skimming can be easily carried out byequipment called a skimmer. The skimmer is, for example, fraudulentlyinstalled into the settlement terminal being used. To install theskimmer into the settlement terminal, a criminal secretly opens ahousing of the settlement terminal to install the skimmer inside thehousing, and then closes the housing. If the skimmer is installed intothe settlement terminal, the skimmer accumulates card data every timethe settlement terminal is used. Card data accumulated in the skimmercan be copied down to blank cards, which are new cards having the samestandards as the various legitimate cards, by scanning the blank cards.Therefore, fraudulent electronic payment is possible by the illegal useof such counterfeit cards, onto which the card data of other people hasbeen copied.

To solve such a problem, a settlement terminal with a switch fordetecting the opening and closing of the housing is proposed. Thesettlement terminal announces that the housing has been opened, once theswitch has detected the opening of the housing. A settlement terminallike this is disclosed in, for example, Japanese Patent Laid-OpenPublication No. 2001-256566.

In the settlement terminal disclosed in the Japanese Patent Laid-OpenPublication No. 2001-256566, however, if the criminal knows the positionof the switch, it is conceivable that the criminal could open thehousing after modifying the settlement terminal so as not to activatethe switch. In this case the criminal can install the skimmer inside thehousing without anybody noticing.

SUMMARY OF THE INVENTION

An object of the present invention is to prevent the skimming of carddata used in electronic payment.

A settlement terminal according to the present invention focusesattention on a phenomenon occurring during executing a fraudulent act,in which the settlement terminal is turned on and off several times whena skimmer is installed into the settlement terminal. The settlementterminal detects the power-on/off of the settlement terminal, anddetermines abnormality in the detected power-on/off event in accordancewith an abnormal power-on/off definition stored in a memory. When thepower-on/off is determined to be abnormal, the settlement terminal sendswarning information to a settlement organ computer in a settlementorgan.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present invention and many of theattendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is a perspective view schematically showing the externalappearance of a settlement terminal according to an embodiment of thepresent invention;

FIG. 2 is a block diagram showing the electric connection of each partprovided in the settlement terminal;

FIG. 3 is a block diagram showing the circuitry of an electric powersupply path; and

FIG. 4 is a flowchart showing the flow of a power-on/off monitoringprocess.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described with referenceto the accompanying drawings. A settlement terminal according to thisembodiment is connectable to a settlement organ computer of a financialorgan as a settlement organ through a communication line. The settlementterminal connected to the settlement organ computer accepts payment by acard such as a credit card, or a cash card used as a debit card (insteadof cash). This is possible with the use of data communication with thesettlement organ computer. In the card used in the settlement terminal,there is a magnetic stripe or an IC chip. In the case of the creditcard, a credit card number (being information specific to the card) isstored as card data on the magnetic stripe or IC chip of the card. Inthe case of a cash card, stored card data may comprise an accountnumber, a predetermined personal identification number, and the like(being information specific to the card).

FIG. 1 is a perspective view schematically showing the externalappearance of a settlement terminal 1.

As shown in FIG. 1, the settlement terminal 1 has a magnetic card readersection 4 on the right side of a housing 2 when viewed from an operatorside of the settlement terminal 1. The magnetic card reader section 4has a slit-shaped reading groove 3, into which the magnetic stripe of acard (being a recording medium for identifying information) is insertedand pulled toward the operator. This magnetic card reader section 4contains a magnetic card reader 10 (refer to FIG. 2) for reading datarecorded on the magnetic stripe of the card.

In the top face of the housing 2, a keyboard 5, a display 6, and areceipt outlet 8 are successively arranged from the operator side of thesettlement terminal 1 (the downstream side of a card pull-out direction)to the rear side (the upstream side of the card pull-out direction). Thekeyboard 5 has such an external appearance that various keys such asnumeric keys 5 a from “0” to “9” (for inputting an amount and the like)and function keys 5 b are arranged block-by-block. The thin andflat-shaped display 6 is an LCD (liquid crystal display) for displayingthe contents of a transaction, a guide to operation or the like. Thereceipt outlet 8 is an outlet for issuing a receipt (not illustrated)printed by a printer 7 (refer to FIG. 2) contained in the housing 2. Thereceipt outlet 8 is formed in a printer cover 9 detachably attached tothe housing 2 in such a manner as to cover the printer 7 contained inthe housing 2.

A power supply switch SW for turning on and off the settlement terminal1 is provided on the side of the housing 2. When the power supply switchSW is turned on, electric power is supplied to each part of thesettlement terminal 1, and a microcomputer 15 to which the electricpower is supplied makes the settlement terminal 1 workable. Operation inthe case where the power supply switch SW is turned off will bedescribed later on.

The settlement terminal 1 has a PIN pad 11 which is separate from thehousing 2. The PIN pad 11 is a personal identification number inputdevice for inputting a personal identification number, predeterminedcard-by-card. The PIN pad 11 comprises a display 12, a keyboard 13, anda card reader and writer section 14. The contents of the transaction, aguide to operation, and the like are displayed on the display 12. Thekeyboard 13 is composed of a group of various keys such as numeric keysfrom “0” to “9,” for inputting the personal identification number. Thecard reader and writer section 14 reads/writes various types of datafrom/into the IC card.

FIG. 2 is a block diagram showing the electric connection of each partprovided in the settlement terminal 1.

The settlement terminal 1 contains the microcomputer 15. Thismicrocomputer 15 controls the operation of each part described abovesuch as the keyboard 5, the display 6, the printer 7, and the magneticcard reader 10 through a bus line 16 and various control circuits (notillustrated). The microcomputer 15 comprises a bus line 16, a CPU(central processing unit) 17, a ROM (read only memory) 18, a RAM (randomaccess memory) 19, and a timer 20. The ROM 18 stores unchangeable datasuch as a computer program (a boot program and a control program). TheRAM 19 changeably stores various types of data. The ROM 18, the RAM 19,and the timer 20 are connected to the CPU 17 through the bus line 16.

A communication I/F 21, a NVRAM (non-volatile random access memory) 22,and a power supply voltage monitoring circuit 23 are connected to themicrocomputer 15 through the bus line 16.

The communication I/F 21 is connected to a settlement organ computerinstalled in a credit card company, a bank or the like, through a relaystation of a public network, a CAFIS (credit and finance informationswitching system) or the like—being a communication line—to execute datacommunication with the settlement organ computer.

The NVRAM 22 is a non-volatile memory for changeably storing data. ThisNVRAM 22 has a monitoring start date and time memory area 22 a, as wellas a power-on/off counter 22 b which are used in the power-on/offmonitoring process described later on. The monitoring start date andtime memory area 22 a stores a date and time (year, month and day, andhour, minute and second) when power-on/off monitoring is started in thepower-on/off monitoring process described later on. The power-on/offcounter 22 b stores a number of times the power supply switch SW isturned on or off since the initialization of the power-on/offmonitoring. When the settlement terminal 1 is shipped out from themanufacturer, the monitoring start date and time memory area 22 a is setat year 0000, month 00 and day 00, and hour 00, minute 00, and second00, and the power-on/off counter 22 b is set at “0.”

The power supply voltage monitoring circuit 23 monitors the voltage ofelectric power supplied from a power control circuit 24 to each part.When the monitored voltage exceeds a predetermined voltage, the powersupply voltage monitoring circuit 23 outputs a turn-on signal to themicrocomputer 15. When the monitored voltage is equal to or less thanthe predetermined voltage, the power supply voltage monitoring circuit23 outputs a PFL (power fail) signal (low-power supply voltagemonitoring signal) to the microcomputer 15. Thus, the power supplyvoltage monitoring circuit 23 functions as detection means for detectingpower-on/off states of the settlement terminal 1.

FIG. 3 is a block diagram showing the circuitry of an electric powersupply path.

The microcomputer 15 operates at +5V, and various units 51 such as thedisplay 6 and the printer 7 operate at +12V or +24V. Accordingly, inthis embodiment, a power supply circuit 102 connected to a commercialpower supply 101 is structured so as to supply +5V to the microcomputer15, and +12V or +24V to the various units 51.

The foregoing power supply switch SW can connect and disconnect electricpower supply from the power supply circuit 102 to each part. The statusof the electric power supply from the power supply circuit 102 to eachpart is monitored by the power supply voltage monitoring circuit 23, asdescribed above. When the voltage of the electric power supplied fromthe power control circuit 24 to each part is equal to or less than thepredetermined voltage, the power supply voltage monitoring circuit 23outputs a PFL (power fail) signal (low-power supply voltage monitoringsignal) to not only the microcomputer 15 but also to the power controlcircuit 24. Upon receiving the PFL (power fail) signal from the powersupply voltage monitoring circuit 23, the power control circuit 24supplies electric power stored in the power supply circuit 102 to themicrocomputer 15 so as to maintain the microcomputer 15 in a workablestate as long as the electric power lasts.

Various processes which are executed by the CPU 17 following thecomputer program will now be described.

A settlement processing will be described first. In the case of asettlement processing involving a credit payment, the settlementterminal 1 waits for the input of settlement amount data through thekeyboard 5. The settlement terminal 1 creates credit data (inquiry data)on the basis of data read from the magnetic stripe or the IC chip of thecard and the settlement amount data. It then sends this created creditdata to the settlement organ computer installed in one of the variouskinds of financial organs. The settlement organ computer executes acredit authorization process such as a credit check and amount approvalon the sent credit data, and then sends authorization result data to thesettlement terminal 1. When authorization result data comprises data forapproving the payment, the settlement terminal 1 sends printing data tothe printer 7 in accordance with the authorization result data, so thata credit voucher is issued from the printer 7. A salesclerk makes acustomer sign the issued credit voucher. In the case of a settlementprocessing involving a debit payment, predetermined data communicationis executed with a financial organ such as a bank on the basis of datastored on the IC chip, the personal identification number inputted bythe customer with the use of the PIN pad 11 and the like, in addition todata related to the settlement amount. Then, the settlement amount isdrawn out of the balance on the corresponding account.

FIG. 4 is a flowchart showing the flow of the power-on/off monitoringprocess.

The power-on/off monitoring process is executed to protect card data,stored on the card, from theft. A method for fraudulently obtaining carddata, as described in “discussion of the background,” is that a criminalopens the housing 2 of the settlement terminal 1 to install a skimmerinside the housing 2, and then closes the housing 2. Then, the criminalcopies card data accumulated in the skimmer to blank cards. Focusingattention on a phenomenon occurring during executing a fraudulent act,in which the settlement terminal 1 is turned on and off several timeswhen a skimmer is installed into the settlement terminal 1, thesettlement terminal 1 according to this embodiment monitors thepower-on/off activity of the settlement terminal 1. The settlementterminal 1 according to this embodiment assumes that the settlementterminal 1 is fraudulently modified when there has been an abnormalpower-on/off, and sends a warning to the settlement organ computer.There are two types of power-on/off monitoring processes, that is, oneis for monitoring power-on, and the other is for monitoring power-off.These two types of power-on/off monitoring processes will besuccessively described.

In the case of monitoring power-on events, when the power supply switchSW is turned on, and the power control circuit 24 supplies the electricpower from the power supply to each part of the settlement terminal 1 tostart a boot-up process, the processes shown in FIG. 4 are executed. Inthese processes, it is determined whether or not the power supply switchSW was turned on (step S101). This determination depends on whether ornot the microcomputer 15, functioning as determining means, has receivedthe turn-on signal from the power supply voltage monitoring circuit 23.When it is determined that the power supply switch SW was turned on (YESin step S101), log information is recorded on the monitoring start dateand time memory area 22 a of the NVRAM 22 (step S102), and “1” is addedto the power-on/off counter 22 b of the NVRAM 22 (step S103).

Then, it is determined whether or not the total value of thepower-on/off counter 22 b, to which “1” was added, exceeds a specifiedvalue X (step S104). The “specified value” is defined as a part of theprogram for executing the flowchart shown in FIG. 4, stored in a memorysuch as, for example, the ROM 18, or is stored in a memory such as, forexample, the NVRAM 22 as a program reference value, in order to definean abnormal power-on/off. When the value of the power-on/off counter 22b is equal to or less than the specified value X, the power-on isdetermined to be a normal power supply operation, and the processesshown in FIG. 4 are ended.

On the other hand, if it is determined that the value of thepower-on/off counter 22 b exceeds the specified value X in the step S104(YES in step S104), it is determined whether the monitoring time fromthe start of monitoring the power-on/off to the present time is within aspecified time value (step S105). In this determination, the date andtime when the monitoring of the power-on/off was started is obtainedfrom the monitoring start date and time memory area 22 a of the NVRAM22. The monitoring time is calculated by subtracting the power-on/offstart date and time from the present date and time, and then thecalculated monitoring time is compared with the specified time value.The power-on/off monitoring start date and time is easily obtained byreferring to the oldest date and time of the log information recorded inthe monitoring start date and time memory area 22 a. The “specified timevalue” is defined as a part of the program for executing the flowchartshown in FIG. 4, stored in a memory such as, for example, the ROM 18, oris stored in a memory such as, for example, the NVRAM 22 as a programreference value, in order to define an abnormal power-on/off.

In the step S105, when it is determined that the monitoring time fromthe start of monitoring the power-on/off to the present time exceeds thespecified time value (NO in step S105), the power-on is determined to bea normal power supply operation. Then, the process advances to step S107to execute a monitoring information reset process. In the monitoringinformation reset process, any value recorded in the monitoring startdate and time memory area 22 a is cleared, and the value of thepower-on/off counter 22 b is set at “1.” The reason why the value of thepower-on/off counter 22 b is set at “1” instead of cleared to “0” is tocount the power-on event detected by the process at step S101 at thistime.

In step S105, when the power-on/off has been repeatedly executed withinthe specified time value, and the number of times of the power-on hasbecome the specified value of X or more, it is determined that anabnormal power-on/off operation was executed. Thus, a warninginformation process for sending warning information to the settlementorgan computer through the communication I/F 21 is executed (step S106).

Thus, the processes of steps S102 to S105 are functions for determiningabnormal power-on/off events, which are detected by the power supplyvoltage monitoring circuit 23, including detection means, in accordancewith abnormal power-on/off definition data stored in a memory such asthe ROM 18. When the determination means determines an abnormalpower-on/off from the processes of steps S102 to S105, the function ofmeans for sending the warning information to the settlement organcomputer is performed in step S106.

In the case of monitoring power-off events, on the other hand, when thepower supply switch SW is turned off and power supply to each part isstopped, the power supply voltage monitoring circuit 23 detects that thevoltage of the power supply circuit 102 becomes equal to or less than apredetermined value. Then, the power supply voltage monitoring circuit23 outputs the PFL (power fail) signal to the microcomputer 15 on thebasis of this detection. Thus, the microcomputer 15 determines that thepower supply was turned off (step S101). After that, as in the case ofmonitoring the power-on, the processes of steps S102 to S107 areexecuted. That is, the processes are executed by substituting “power-on”in the processes for monitoring the power-on, with “power-off.” Suchprocesses are executed when the power supply is turned off. In otherwords, as described above, when the voltage of the electric powersupplied from the power control circuit 24 to each part is equal to orless than a predetermined voltage, the power supply voltage monitoringcircuit 23 outputs a PFL (power fail) signal to not only themicrocomputer 15 but also to the power control circuit 24. Uponreceiving a PFL (power fail) signal from the power supply voltagemonitoring circuit 23, the power control circuit 24 supplies themicrocomputer 15 with electric power stored in the power supply circuit102, to maintain the microcomputer 15 in a workable state for as long asthe stored electric power lasts. Accordingly, the microcomputer 15 cancontinue to execute the processes of the flowchart as shown in FIG. 4.

The power-on/off monitoring process is not limited to individuallymonitoring power-on or power-off events. In the power-on/off monitoringprocess, both of the power-on and the power-off events may be monitored.

When the settlement terminal 1 is turned on and off for a number oftimes exceeding the specified value of X within the specified timeperiod, as described above, it is determined that an abnormalpower-on/off operation such as typically attaching a skimmer to thesettlement terminal 1, was performed. Consequently a warning is sent tothe settlement organ computer. Therefore, in the settlement terminal 1according to this embodiment, it is possible to detect the fraudulentevents associated with installing a skimmer, such as a repeat ofpower-on/off events, and to inform the settlement organ computer of afraudulent modification. Accordingly, the settlement organ can takemeasures against the theft of card data, and hence it is possible toprevent the theft of card data before it happens.

In another embodiment, the determination means (steps S102 to S105) maydetermine the abnormality of the power-on/off only during a specifiedtime zone. Namely, prior to the processes shown in FIG. 4, it isdetermined whether or not the present time is in the specified timezone. Only when the current time is within the specified time zone arethe processes shown in FIG. 4 executed. Such a process notes that afraudulent modification, such as attachment of a skimmer to thesettlement terminal 1, is mostly carried out between closing time andopening time while the owner or a responsible person is absent.Accordingly, by defining a time zone between the closing time and theopening time as the “specified time zone,” the processes shown in FIG. 4are executed only when the settlement terminal 1 is turned on duringthis time zone. The “specified time zone” is defined as a part of theprogram for executing the flowchart shown in FIG. 4 stored in a memorysuch as, for example, the ROM 18, or is stored in a memory such as, forexample, the NVRAM 22 as a program reference value, in order to definean abnormal power-on/off.

In a further embodiment, the abnormal power-on/off definition stored ina memory is that “an abnormal power-on/off occurrence exists when thesettlement terminal 1 is turned on or off during the specified timezone.” The determination means may determine that there was the abnormalpower-on/off in the settlement terminal 1 when the settlement terminal 1was turned on or off during the specified time zone. Namely, it isdetermined whether or not the current time is within the specified timezone. When the current time is determined to be within the specifiedtime zone, it is determined that there was an abnormal power-on/off.This embodiment also notes that a fraudulent modification such as theattachment of the skimmer to the settlement terminal 1 is mostly carriedout between closing time and opening time while the owner or aresponsible person is absent. Accordingly, by defining the time zonebetween the closing time and the opening time as the “specified timezone,” it is determined that there was the abnormal power-on/off in thesettlement terminal 1 when the settlement terminal 1 was turned onduring the time zone. The “specified time zone” is defined as a part ofthe program for executing the flowchart shown in FIG. 4 stored in amemory such as, for example, the ROM 18, or is stored in a memory suchas, for example, the NVRAM 22 as a program reference value, in order todefine an abnormal power-on/off.

In the embodiment described above, it may not be determined that therewas an abnormal power-on/off in the settlement terminal 1 even when thesettlement terminal 1 was turned on or off during the specified timezone. When, for example, the settlement terminal 1 was turned on and offfor the number of times exceeding the specified number or this wasperformed within a specified time value, it may be determined that therewas an abnormal power-on/off. To realize such a process, the abnormalpower-on/off definition stored in a memory is that “the settlementterminal 1 is turned on or off during the specified time zone” AND “thenumber of times of the power-on/off exceeds the specified number.”Otherwise, the abnormal power-on/off definition is that “the settlementterminal 1 is turned on or off during the specified time zone” AND “thenumber of times of the power-on/off exceeds the specified number withina specified time value.” To be more specific, in the processes shown inFIG. 4, after it is determined that the settlement terminal 1 was turnedon or off (YES in step S101), and the processes of steps S102 and S103are executed, a determination process in which it is determined whetheror not the current time is within the specified time zone is added. Onlywhen the current time is within the specified time zone may the processadvance to step S104.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

1. A settlement terminal, comprising: means for connecting thesettlement terminal to a settlement organ computer in a settlement organthrough a communication line; means for executing a settlementprocessing with the settlement organ computer via data communicationthrough the communication line; means for detecting a power-on/off eventof the settlement terminal; means for determining whether the detectedpower-on/off event is abnormal, in accordance with a stored abnormalpower-on/off definition; and means for sending warning information tothe settlement organ computer when the detected power-on/off event isdetermined to be abnormal.
 2. The settlement terminal according to claim1, wherein the abnormal power-on/off definition includes a specifiednumber of power-on/off events and a specified time period; and whereinthe determining means determines that the detected power-on/off event isan abnormal power-on/off event if the detection of the power-on/offevent by the detecting means causes a number of detected power-on/offevents to exceed the specified number of power-on/off events within thespecified time period.
 3. The settlement terminal according to claim 2,further comprising a non-volatile memory which includes: (i) a memoryarea that stores a time at which the specified time period begins, and(ii) a counter which is incremented by one each time a power-on/offevent is detected by the detecting means so as to store the number ofdetected power-on/off events.
 4. The settlement terminal according toclaim 1, wherein the determining means only performs the determinationof whether the detected power-on/off event is an abnormal power-on/offevent during a specified time zone.
 5. The settlement terminal accordingto claim 1, wherein the abnormal power-on/off definition includes aspecified time zone; and wherein the determining means determines thatany power-on/off event detected during the specified time zone isabnormal.
 6. The settlement terminal according to claim 1, wherein theabnormal power-on/off definition includes a specified number ofpower-on/off events and a specified time zone; and wherein thedetermining means determines that the detected power-on/off event is anabnormal power-on/off event if the detection of the power-on/off eventby the detecting means occurs within the specified time zone and if thedetection of the power-on/off event by the detecting means causes anumber of detected power-on/off events to exceed the specified number ofpower-on/off events.
 7. The settlement terminal according to claim 6,further comprising a non-volatile memory which includes a counter whichis incremented by one each time a power-on/off event is detected by thedetecting means so as to store the number of detected power-on/offevents.
 8. The settlement terminal according to claim 1, wherein theabnormal power-on/off definition includes a specified number ofpower-on/off events, a specified time period, and a specified time zone;and wherein the determining means determines that the detectedpower-on/off event is an abnormal power-on/off event if the detection ofthe power-on/off event by the detecting means occurs within thespecified time zone and if the detection of the power-on/off event bythe detecting means causes a number detected of power-on/off events toexceed the specified number of power-on/off events within the specifiedtime period.
 9. The settlement terminal according to claim 8, furthercomprising a non-volatile memory which includes: (i) a memory area thatstores a time at which the specified time period begins, and (ii) acounter which is incremented by one each time a power-on/off event isdetected by the detecting means so as to store the number of detectedpower-on/off events.
 10. The settlement terminal according to claim 1,wherein the power-on/off event is defined as only an event of turningthe settlement terminal on.
 11. The settlement terminal according toclaim 1, wherein the power-on/off event is defined as only an event ofturning the settlement terminal off.
 12. The settlement terminalaccording to claim 1, wherein the power-on/off event is defined as anevent of turning the settlement terminal either on or off.
 13. Asettlement terminal, comprising: a communication section which connectsthe settlement terminal to a settlement organ computer in a settlementorgan through a communication line, the settlement terminal beingoperable to execute settlement processing with the settlement organcomputer via data communication through the communication line; amonitoring circuit which detects a power-on/off event of the settlementterminal; and a control section which determines whether the detectedpower-on/off event is abnormal, in accordance with a stored abnormalpower-on/off definition, and which sends warning information to thesettlement organ computer when the detected power-on/off event isdetermined to be abnormal.
 14. The settlement terminal according toclaim 13, wherein the abnormal power-on/off definition includes aspecified number of power-on/off events and a specified time period; andwherein the control section determines that the detected power-on/offevent is an abnormal power-on/off event if the detection of thepower-on/off event by the monitoring circuit causes a number of detectedpower-on/off events to exceed the specified number of power-on/offevents within the specified time period.
 15. The settlement terminalaccording to claim 9, wherein the control section only performs thedetermination of whether the detected power-on/off event is an abnormalpower-on/off event during a specified time zone.
 16. The settlementterminal according to claim 13, wherein the abnormal power-on/offdefinition includes a specified time zone; and wherein the controlsection determines that any power-on/off event detected during thespecified time zone is abnormal.
 17. The settlement terminal accordingto claim 13, wherein the abnormal power-on/off definition includes aspecified number of power-on/off events and a specified time zone; andwherein the control section determines that the detected power-on/offevent is an abnormal power-on/off event if the detection of thepower-on/off event by the monitoring circuit occurs within the specifiedtime zone and if the detection of the power-on/off event by themonitoring circuit causes a number of detected power-on/off events toexceed the specified number of power-on/off events.
 18. The settlementterminal according to claim 13, wherein the abnormal power-on/offdefinition includes a specified number of power-on/off events, aspecified time period, and a specified time zone; and wherein thecontrol section determines that the detected power-on/off event is anabnormal power-on/off event if the detection of the power-on/off eventby the monitoring circuit occurs within the specified time zone and ifthe detection of the power-on/off event by the monitoring circuit causesa number detected of power-on/off events to exceed the specified numberof power-on/off events within the specified time period.